[Ether]

Originally Posted by dsirovica

I meant to say was this:

P(motor heating)=I^2R
But I is not purely Vbatt/Rmotor, it is:
I= (Vbatt-Vback-emf)/Rmotor
.

That's closer. "Vbatt" should be Vmco (motor controller output). But depending on the motor's inductance and the motor controller's switching frequency, there may be ripple current. That causes extra motor heating and power loss. (That's why I said "I is RMS current").